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Joel Ullom (Fed)

Dr. Joel Ullom leads the NIST Quantum Sensors Division. He is also a Lecturer in the Department of Physics at the University of Colorado Boulder. Dr. Ullom has worked in the fields of low temperature sensors, quantum electronics, and cryogenic systems since 1994. During this time, he has done research to understand and improve the performance of superconducting transition-edge sensors. He has also worked to develop different types of refrigerators including microcoolers based on quantum tunneling and macrocoolers that reduce the need for liquid cryogens. Dr. Ullom has developed and disseminated a variety of instruments based on multiplexed arrays of cryogenic sensors.

Research Interests

  • cryogenic sensors
  • multiplexed readout techniques
  • advanced cryogenics
  • radiation detection
  • applications of cryogenic sensors in materials analysis, astrophysics, cosmology, fundamental parameters, and quantum information science

Awards

Publications

Spectroscopic Measurements and Models of Energy Deposition in the Substrate of Quantum Circuits by Natural Ionizing Radiation

Author(s)
Joseph Fowler, Paul Szypryt, Raymond Bunker, Ellen Edwards, Ian Fogarty Florang, JIANSONG GAO, Shannon Hoogerheide, Ben Loer, Hans Mumm, Nathan Nakamura, John Orrell, Elizabeth M. Scott, Jason Stevens, Daniel Swetz, Brent VanDevender, Michael Vissers, Joel Ullom
Naturally occurring background radiation is a potential source of correlated decoherence events in superconducting qubits that will challenge error-correction

Kinetic inductance current sensor for visible to near-infrared wavelength transition-edge sensor readout

Author(s)
Paul Szypryt, Douglas Bennett, Ian Fogarty Florang, Joseph Fowler, Jiansong Gao, Andrea Giachero, Ruslan Hummatov, Adriana Lita, John Mates, Sae Woo Nam, Daniel Swetz, Joel Ullom, Michael Vissers, Jordan Wheeler
Single-photon detectors based on the superconducting transition-edge sensor are used in a number of visible to near-infrared applications, particularly for

Few-electron highly charged muonic Ar atoms verified by electronic K xrays

Author(s)
Takuma Okumura, Toshiyuki Azuma, Douglas Bennett, W. Bertrand (Randy) Doriese, Malcolm Durkin, Joseph Fowler, Johnathon Gard, Tadashi Hashimoto, Ryota Hayakawa, Yuto Ichinohe, Paul Indelicato, Tadaaki Isobe, Sohtaro Kanda, Daiji Kato, Miho Katsuragawa, Naritoshi Kawamura, Yasushi Kino, Nao Kominato, Yasuhiro Miyake, Kelsey Morgan, Hirofumi Noda, Galen O'Neil, Shinji Okada, Kenichi Okutsu, Nancy Paul, Carl D. Reintsema, Toshiki Sato, Dan Schmidt, Kouichiro Shimomura, Patrick Strasser, Daniel Swetz, Tadayuki Takahashi, Shinichiro Takeda, Soshi Takeshita, Motonobu Tampo, Hideyuki Tatsuno, Tong Xiao-Min, Joel Ullom, Shin Watanabe, Shinya Yamada, Takuma Yamashita
Electronic K x rays emitted by muonic Ar atoms in the gas phase were observed using a superconducting transition-edge-sensor microcalorimeter. The high

Patents (2018-Present)

Compact Low-power Cryo-Cooling Systems For Superconducting Elements

NIST Inventors
Joel Ullom and Vincent Kotsubo
A compact, low power cryo-cooler for cryogenic systems capable of cooling gas to at least as low as 2.5 K. The cryo-cooler has a room temperature compressor followed by filtration. Within the cryostat, four counterflow heat exchangers precool the incoming high-pressure gas using the outflowing low
X-Ray Spectrometer

X-Ray Spectrometer

NIST Inventors
Kevin L. Silverman , Carl D. Reintsema , Galen O'Neil , Luis Miaja Avila , Daniel Swetz , W.Bertrand (Randy) Doriese , Dan Schmidt , Bradley Alpert , Joseph Fowler , Joel Ullom and Ralph Jimenez
This invention includes: an x-ray plasma source that produces primary x-rays; an x-ray optic that transmits and focuses the primary x-ray onto a sample jet from which fluorescence x-ray are emitted; and a microcalorimeter array detector that measures the energy of the incoming fluorescence x-rays
Created October 9, 2019, Updated October 23, 2023